Method _load_existing_graph

rust-core/src/codegraph/parser.rs:899–916

尝试从本地数据库加载现有的图

(&self, dir: &Path)

    /// 尝试从本地数据库加载现有的图
    fn _load_existing_graph(&self, dir: &Path) -> Result<Option<PetCodeGraph>, String> {
        use crate::storage::PersistenceManager;
        
        // 使用项目路径作为项目ID
        let project_id = dir.file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("default");
        
        let persistence = PersistenceManager::new();
        match persistence.load_graph(project_id) {
            Ok(Some(graph)) => Ok(Some(graph)),
            Ok(None) => Ok(None),
            Err(e) => {
                warn!("Failed to load existing graph: {}", e);
                Ok(None)
            }
        }
    }

    /// 加载文件哈希值
    fn _load_file_hashes(&self, dir: &Path) -> Result<HashMap<String, String>, String> {